<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <div style="height: 1000px;background-color: #ddd;"></div>
    <div style="position: fixed;right:200px;bottom: 100px;">返回顶部</div>
</body>
</html>